It's not rocket science. Far from it. It's religion and it's stupid. That's probably why some religious people fail to understand that hate and fear are negative emotions, the realm of Satan, that override the human reasoning capabilities God gave people and love. That is all.
Christmas is a weird holiday. On the one hand you are celebrating the birth of a mythical figure that a ridiculous number of people believe really exists, while waiting around for another mythical figure to arrive with a pantload of presents that almost everyone knows is ridiculous to believe in. If only young children could develop the same skepticism about the Baby Jesus as they eventually do about Father Christmas.
The dichotomy seems to stem from the fact that Baby Jesus is expected to return only once, on Judgment Day, which will, rumor has it, come without warning (anxiety!). Father Christmas though has an annual, rigidly scheduled arrival date. So empirical observation quickly dispels any belief in the latter after just a few years of disappointment. Baby Jesus was smart not to give himself any hard deadlines like that. He can wank off as long as he wants and get down to this Armageddon business whenever it suits him. He didn't give humans a metric on which to measure his due diligence. Father Christmas, conversely, pretty much structured himself right out of existence.
These presents that Santa is supposed to bring also represent a conundrum. If you do nothing, no presents magically materialize under the tree. People have to actively facilitate this present gathering by shopping for and wrapping presents themselves, so they quickly realize that "Santa helps those who help themselves." Jesus encourages pretty much the same behavior in his followers, but he demands less actual participation in the process. You just have to believe in him and then "everything happens for a reason" or "it's God's plan."
I think Santa's self sacrificing himself out of existence actually benefits people more than Jesus' self sacrificing himself on the Cross to purge humanity's sins (yes, I realize that's Easter, not Xmas). Santa shows people that you pretty much create your own reality and pull yourself up by your bootstraps. No mythical being needed. That's a much more empowering message.
I know you don't exist. But I am out of options when it comes to the more extremist of your devotees. Is there any way you can tell them to stop being so hypocritical and mean to non-believers. It's not cool to wish eternal hellfire and damnation on others. Even the Bible says so. Sometimes. Other times it says kill non-believers. It's a really confusing screed, honestly.
A good day to you.